Suggestion: TCP keepalive Support about bore HOT 2 CLOSED

use socket2::{SockRef, TcpKeepalive};

// ...

impl Server {
    // ...

    /// Start the server, listening for new connections.
    pub async fn listen(self) -> Result<()> {
        let this = Arc::new(self);
        let addr = SocketAddr::from(([0, 0, 0, 0], CONTROL_PORT));
        let listener = TcpListener::bind(&addr).await?;

        let ka = TcpKeepalive::new().with_time(Duration::from_secs(30)); // <- new line
        SockRef::from(&listener).set_tcp_keepalive(&ka)?; // <- new line
// ...